1. Field of the Invention
The present invention relates to an image processing apparatus comprising an optical unit in which an optical instrument related to image processing is mounted.
2. Description of the Related Art
Image processing apparatuses, such as copy machines, printers, and facsimiles are housing the optical instruments for image processing in their body chassis.
Also, as have been described in the prior art 1 (Japanese Unexamined Patent Publication No. 2002-187308), with respect to the image processing apparatuses in these days, the optical instruments relevant to image processing, such as the light source (such as, razor beam outputting apparatus) for performing beam light output for writing an electrostatic latent image onto, for example, an image supporter (for a typical example, photoreceptor drum), one or a plurality of deflecting mirrors for guiding beam light to the photoreceptor drum, the fθ lens for performing fθ amendment of beam light, and the polygon mirror for driving beam light to scan in the direction of the axis of the photoreceptor drum, are mounted in the chassis that are made from a single-casting separately from the structures of the bodies, thereby being unitized as the optical unit. The relative positions between the optical instruments are, therefore, determined with high accuracy through the chassis manufactured with high dimensional accuracy by single casting.
On the other hand, the conventional image processing apparatuses are generally provided with protruding legs, that contact with the installation surface, on four points on the undersurface of the apparatus body (generally, four corners of the rectangular undersurface). Moreover, in the prior art 2 (Japanese Unexamined Patent Publication No. 2001-117302), legs (feet) for apparatus stability are provided in three points between the image forming apparatus body and the installation surface in a manner so as to form a rough triangle.
However, as described in Japanese Unexamined Patent Publication No. 2002-187308, even if the optical instruments are unitized, when the supporting member in the side of the apparatus body (the frame of the body side) for supporting the optical unit is warped by such as differences of elevation (distribution of unevenness) on the installation surface of the apparatus, there still remains a problem that the accuracy of positioning of the optical instruments is degraded. Particularly, when legs are provided in four points (four corners) on the undersurface of the apparatus body, the supporting member (frame) in the side of the apparatus body may easily warped by the differences of elevation on the installation surface with which those legs in four points contact.
In addition, as described in Japanese Unexamined Patent Publication No. 2001-117302, even when legs are provided in three points on the undersurface of the apparatus body in a manner so as to form a rough triangle, the supporting member (frame) in the side of the apparatus body may warped because of its own weight, and in if so, there occurs a problem that the accuracy of positioning of the optical instruments may be degraded by the warp of said supporting members, depending on the supporting structure of the optical unit.
Consequently, this invention has been invented considering the foregoing conditions, and the purpose of this invention is to provide the image processing apparatus having the structure that does not easily allow its accuracy of positioning of the optical instruments related to image processing to be influenced from the condition of the installation surface of the apparatus body.